NEWAYGO COUNTY, MI -- Marcus Wallis, one of two people accused of lying to prosecutors in the investigation of Amanda Lankey's 2004 slaying, has pleaded guilty to a misdemeanor.

Wallis, 26, on Monday, April 14, entered a plea to making false statements to police, reduced from perjury. He was sentenced to 60 days in jail to be served on weekends.

Perhaps more importantly to the family of Lankey, a judge also ordered Wallis to take a polygraph test on facets of the investigation.

Wallis and his mother, Candace Wallis-Baumgartner, in 2012 were accused of lying to prosecutors trying to solve the homicide of the 13-year-old Lankey, whose body was found in the Manistee National Forest about two weeks after she went missing in June 2004.

Wallis-Baumgartner is the sister of a Cecil Wallis Sr., a person-of-interest in the homicide who became a focus of police after he was charged in 2011 with two decade-old sexual assaults on teens.

Wallis Sr. committed suicide while out on bond.

Amanda Lankey, 13, was killed in 2004

Prosecutors say Wallis-Baumgartner, a former White Cloud police officer, lied about being asked to help at the crime scene where Lankey's body was found. They also allege she lied about falsifying a police report to cover-up for a drunken driving incident involving her brother in the late 1990s.

She pleaded guilty to a misdemeanor in March and was sentenced to 30 weekends in jail. She also was ordered to take a polygraph.

Marcus Wallis was accused of lying about whether he did anything to help Cecil Wallis Sr. find one of the sex-assault victims related to the 2011 charges.

Prosecutors alleged that Marcus Wallis asked relatives of a man who knew the victim if they knew her whereabouts.

The plea agreements for both Wallis-Baumgartner and Marucs Wallis prohibit them from getting the misdemeanor convictions expunged.